The National Security Agency isn't the only government entity secretly collecting data from people's cellphones. Local police are increasingly scooping it up, too. Armed with new technologies, including mobile devices that tap into cellphone data in real time, dozens of local and state police agencies are capturing information about thousands of cellphone users at a time, whether they are targets of an investigation or not, according to public records obtained by USA TODAY and Gannett newspapers and TV stations.

Armed with new technologies, including mobile devices that tap into cellphone data in real time, dozens of local and state police agencies are capturing information about thousands of cellphone users at a time, whether they are targets of an investigation or not, according to public records obtained by USA TODAY and Gannett newspapers and TV stations.

The records, from more than 125 police agencies in 33 states, reveal:

• About one in four law-enforcement agencies have used a tactic known as a "tower dump," which gives police data about the identity, activity and location of any phone that connects to the targeted cellphone towers over a set span of time, usually an hour or two. A typical dump covers multiple towers, and wireless providers, and can net information from thousands of phones.

In most states, police can get many kinds of cellphone data without obtaining a warrant, which they'd need to search someone's house or car. Privacy advocates, legislators and courts are debating the legal standards with increasing intensity as technology — and the amount of sensitive information people entrust to their devices evolves.

Organizations such as the American Civil Liberties Union and Electronic Privacy Information Center (EPIC) say the swelling ability by even small-town police departments to easily and quickly obtain large amounts of cellphone data raises questions about the erosion of people's privacy as well as their Fourth Amendment protections against unreasonable search and seizure.

"I don't think that these devices should never be used, but at the same time, you should clearly be getting a warrant," said Alan Butler of EPIC.